Mechanical pencil with an automatic feed mechanism



B. SPECTOR Nov. 10, 1959 MECHANICAL PENCIL WITH AN AUTOMATIC FEEDMECHANISM Filed Oct. 26, 1956 2 Sheets-Sheet l NOV. 10, 1959 B, SPECTOR2,911,948

MECHANICAL PENCIL WITH AN AUTOMATIC FEED MECHANISM Filed oct.y 2e, 195ez sheets-sheet 2 FIG. I4.

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BAR ucH sPEcToR 2041 ATTQRNEY.'

United States Patent O MECHANICAL PENCIL WITH AN AUTOMATIC FEEDMECHANISM Baruch Spector, Massapequa Park, N.Y., assiguor of onehalf toNovera H. Spector, Merrick, N.Y.

Application October 26, 1956, Serial No. 618,467

i 3 Claims. (Cl. 1Z0-14.1)

This invention relates to a mechanical pencil with an automatic feedmechanism.

The princip-al object of this invention is the provision of a mechanicalpencil embodying an automatic pressure feed mechanism whichautomatically feeds the lead (writing element) under the pressure whichis normally exerted upon the pencil when it is used in conventionalmanner.

The writing element (herein designated as the lead) is encased in thepresent device in a sleeve which supports it and prevents it frombreaking during the writing operation. This sleeve is adapted to movelongitudinally relative to the pencil holder, that is, the main casingin which the lead and the mechanism are mounted and which is held in thehand when writing. It is this relative movement between the sleeve andthe main casing first in one direction and then in the oppositedirection which provides the force necessary to feed the lead in thepresent device. When the pencil is held in the hand and is used inconventional manner on a writing surface, the lower end of the sleeve isbrought to bear against said Writing surface while pressure is appliedto the outer casing in downward direction. As the lead is consumed inwriting, the sleeve retracts into the outer casing, or stated moreprecisely, the outer casing descends relative to the sleeve. When thepressure is released, that is, when the pencil is lifted from thewriting surface, spring means return the sleeve to its forwardlyprojected position, this time beyond the lead since a portion of thelead has now been consumed. Further pressure upon the outer casing whenwriting is resumed will advance the lead to writing position and as itis consumed the sleeve will rise. This process is continued until thelead is fully consumed.

Another important object of the invention is the provision of amechanism as above described with the additional feature of an automaticrefill mechanism which replaces the used or consumed leads with newones. This rell mechanism includes a magazine which contains a pluralityof replacement leads and spring means for urging them seriatim into thesleeve above mentioned.

The principles above mentioned may be applied in the several forms ofthe invention shown in the drawing. But in addition to the variousmechanisms which may be employed in carrying out these principles, thereis the important feature that said principles and said mechanisms may beapplied to leads of various conventional and unconventional shapes. Forexample, two conventional shapes which are illustrated in the drawingare the cylindrical and rectangular shapes commonly used. But inaddition, there is the provision in the present invention of cylindricaland rectangular shapes which are provided with ne ribs extendinglongitudinally of the lead. These fine ribs are adapted to be compressedby the sleeve which holds the lead and they thereby provide a press iitwhich holds the lead securely in the sleeve while permitting it toadvance as it is consumed.

It is therefore not only the object of this invention to ice provide apencil which is adapted to utilize ribbed lead of the characterdescribed, but it is also an object of the invention to provide ribbedlead of this character for the purpose above set forth and adapted foruse in said pencil as well as in other mechanical pencils known to-theart.

The invention is illustrated in the accompanying drawing in which:

Fig. 1 is a side view, partly broken away and in section, showing amechanical pencil made in accordance with one form of this invention.

Fig. 2 is a longitudinal section therethrough on the line 2 2 of Fig. 1.

Fig. 3 is a transverse section on the line 3-3 of Fig. 2, showing thecasing in open position.

Fig. 4 is a similar view on the line 4-4 of Fig. 2. t

Fig. 5 is another transverse section on the line 5-5 of Fig. 2. v

Fig. 6 is a side view of one of the elements shown in Fig. 1.

Fig. 7 is a transverse section through a conventional rectangular stickof lead which may be used in the pencil illustrated in Figs. 1 to 6inclusive.

Fig. 7A is a transverse section through a rectangular stick of leadprovided with longitudinally extending ribs.

Fig. 8 is a longitudinal section through a mechanical pencil made inaccordance with a second form of this invention.

Fig. 9 is a forward end view of said pencil looking in the direction ofarrows 9, 9 in Fig. 8.

Fig. 10 is a top end view looking in the direction of arrows 10, 10 inFig. 8.

Fig. l1 is a fragmentary view of the upper end of the outer casing ofthe pencil shown in Fig.

Fig. 12 is a fragmentary view of one of the elements of the pencil shownin Fig. 8.

Fig. 13 is a transverse section through a cylindrical stick of leadadapted for use in the pencil shown in Figs. 8 to 12 inclusive.

Fig. 13A is a transverse section on the line 13A-13A of Fig. 13B, andshowing a longitudinally ribbed cylindrical stick of lead adapted foruse in the pencil shown in Figs. 8 to 12.

Fig. 13B is a side view of said ribbed stick of lead.

Fig. 14 is a longitudinal section through va refill-type of mechanicalpencil made in accordance with a third form of this invention. v

Fig. 15 is a transverse section on the line 15-15 of Fig. 14.

Fig. 16 is a fragmentary section showing a modification `of the magazineand refill mechanism of Figs. 14 and 15.

Fig. 17 is a transverse section on the line 17-17 of Fig. 16.

Fig. 18 is a longitudinal section through another pencil made inaccordance with still another form of this im vention.

Fig. 19 is a transverse section on the line 19-19 of of Fig. 18.

Referring now to the first form of this invention and Figs. 1 to 6 ofthe drawing, it will be observed that a casing 10 is provided whichconsists of two sides 12 and 14 which are pivotally connected to eachother by means of a hinge pin or pintle 16 which extends substantiallythe full length of the -two casing side members 12 and 14. Each sideelement 12 and 14 is a three-sided member of dove-tail shape incross-section or end view.' Clip portions 18 and 20 on the two sidemembers are engage'- able with each other to hold Ithe casing closed asFigs. 1 and 2 clearly show.

Mounted within the two casing side members 12 `and 14 are guide bars 22and 24. These guide bars have tapered or converging sides so as todove-tail intothe casing side members 12 and 14. It will be observed inFig. l that these guide bars are spaced from each other when the casingis closed so as to provide a channel 26 between themextendinglongitudinally of the casing. The major portion of the twoV guide bars.is disposed within the casing and occupying approximately two-thirds ofits length, leaving the upper third of the casing vacant. Projectingdownwardly from the casing and from the main body of the two guide bars22 and 24 are tapered portions of said guide bars designated in thedrawing as 28 and 30 respectively. The lower ends ofthese taperedportions are rounded olf as the drawing clearly shows in Fig. 1 toprovide a smooth bearing surface for application to the paper on whichthe pencil is to be used.

Occupying channel 26 is a pair of spacer bars 32 and 34 respectivelywhich are best shown in Fig. 2, one of said bars, 34, being Valso shownin Fig. 6. These spacer bars 32 and 34 are substantially the same lengthas the guide bars 22 and 24. Like the guide bars, spacer bars 32 and 34are provided at their lower ends with tapered portions 36 and 38 whichare rounded olf to provide a suitable bearing surface for the writingpaper. It will be observed in Fig. 2 that a channel 40 separates the twovspacer bars 36 and 38 and it will now be seen that the writing elementor lead 42 occupies said channel 40. Consequently, the lead is held inplace against lateral displacement by the two guide bars 22 and 24 andthe two spacer bars 32 and 34.

In this form of the invention, the channel which is provided betweenguide bars 22 and 24 on the one hand and between spacer bars 32 and 34on the other hand, is rectangular in cross-section. It is designed toreceive the rectangular lead 42 whose cross-sectional shape is shown inFig. 7. To assist in preventing the lead from slipping longitudinallyout of its channel, a leaf spring 44 is provided in the tapered endportion 28 of guide bar 22. This spring tensionally and frictionallyengages the lead and holds it against accidental longitudinaldisplacement in downward direction. This shape of lead is conventionaland consequently 'some external gripping means, such as the spring lastmentioned, is required to prevent such accidental displacement.

`But Fig. 7A discloses a lead 46 which requires no such externalgripping means to hold it in place. This stick of lead is alsorectangular in cross-sectional -shape but it is provided with finelongitudinally extending ribs 48 which project outwardly therefrom,preferably along its four corners. These line ribs serve as spacers andbearing surfaces between the lead and the corners of the channel inwhich the lead is disposed. When the lead is inserted into said channel,these tine ribs are squeezed or compressed between the corners of thechannel and the corners of the lead and a press-tit is thereby provided.In this connection, it will be understood that there is relativelylittle clearance between the side walls of the lead and the side wallsof the channel. The height of thene ribs is therefore necessarilylimited and it exceeds only slightly the extent of clearance ortolerance between the lead and the walls of the channel. These ribs alsocompensate for variations in tolerance between the walls of the lead andchannel.

Occupying the same channel as the lead is a pusher bar 50 whose lowerend abuts the upper end of the lead. This pusher bar performs twofunctions: It prevents upward dislodgment of the lead while it is beingused and also provides the means of bearing down on the lead during thewriting operation, and it also is involved in the operation by which thelead is advanced in the pencil as it is consumed. Two clutch members 60and 62 engage the pusher bar 50. The upper clutch 60 may be designatedthe holding clutch and the lower clutch 62 may be designated the feedclutch. The upper holding clutch 60 projects outwardly through anopening 64 in the casing. Opposite said opening 64 is a rod 66 whichextends between and bears against the two clutches 60 and 62. The lowerfeed clutch 62 is contained entirely within the casing and one enddesignated 62a engages a fulcrum 68 provided in a cutout 70 in whichsaid lower feed clutch 62 is disposed. A torsion spring 72 engages saidlower feed clutch and urges it to swing in counterclockwise directionabout said fulcrum 68 as viewed in Fig. 2. This has the effect of urgingrod 66 upwardly and to cause the upper holding clutch 60 to swing incounter-clockwise direction, also as viewed in Fig. '2.

When the pencil is held upon a sheet of paper in conventional manner, itis the casing 10 which is held in the hand and pressed downwardly. Thecurved lower ends of the tapered portions 28 and 30, and 36 and 38 bearagainst the paper and oppose the downward pressure exerted upon thecasing. The upper end or edge 74 defined by opening 64 serves as ashoulder engaging the outwardly projecting end of the upper holdingclutch 60 and the downward pressure exerted on and through the casingtends to assist the rod 66 in swinging said clutch in counter-clockwisedirection. The effect of such action upon the holding clutch 60 is tocause it to grip the pusher bar 50 as is clearly shown in Fig. 2.Consequently, any downward pressure upon the casing during the writingoperation is transmitted through the upper holding clutch 60 to thepusher bar 50 and through said pusher bar to the lead itself.

It has above been stated that the rounded ends of tapered portions 28,30, 36 and 38 bear against the paper during the writing operation. Asthe lead is consumed, it is automatically advanced by the pressureexerted through the casing and upper holding clutch 60 and pusher bar50. Consequently, relative movement must take place betweensaid casing,holding clutch and pusher bar on the one hand and the tapered portions28, 30, 36 and 38 on the other hand. What happens is that these taperedportions remain stationary since they bear against the writing surfaceand the other elements, namely, the casing, holding clutch 60 and pusherbar 5t), descend in direct proportion tothe wear upon the lead.

It will now be observed that a shoulder 76 is provided at the upper endsof tapered portions 36 and 38 of the spacer bars and that said shoulderis engageable with a ange 78 formed at the lower end of each casingmember. Abutment of the shoulder against the ange limits the relativemovement between the spacer bars and the casing in one direction butpermits relative movement in the opposite direction. At this point itmay be stated that the spacer bars 32 and 34 are secured to the guidebars 22 and 24 by any conventional means so that all four bars moveintegrally with each other and constitute a sleeve for the lead. Whenthe lead is consumed during writing, the casing, upper holding clutch 60and pusher bar 50 descend so as to space the flanges 78 from theshoulders 76. This downward movement of the casing, holding clutch andpusher bar takes place against the action of compression spring 80 whoseupper end abuts said holding clutch and whose lower end rests upon aplate 82 which is connected to the guide and spacer bar assembly lastmentioned and designated as the sleeve for the lead. The fulcrum 68above mentioned is shown to be formed at the lower end of said plate 82.A pin 84 is secured to the upper end of said plate 82 and it extendsthrough an opening 86 in the upper holding clutch 60. This pin serves noother function than to support the compression spring 80 and to hold itin place between said upper holding clutch and said plate 82.

When the pencil is lifted from the writing surface, spring 80 is free tomove the upper clutch member 60, and casing 10 upwardly while moving theguide and spacer bar assembly downwardly so as to re-engage theshoulders 76 with the flanges 78. The pusher bar 50 does not move withthe casing and upper holding clutch ,but rather remains fixed to theguide and spacer bar assembly by reason of the action of the feed clutch62 thereon. Torsion spring 72 causes the feed clutch 62 to engage thepusher bar 50. This is shown in Fig. 2. Since said torsion spring andfeed clutch are supported by the guide and spacer bar assembly and notby the casing 10, they will hold the pusher bar fixed in positionrelative to said guide and spacer bar assembly. The action ofcompression spring 80 on the upper holding clutch 60 causes said clutchto swing in clockwise direction as viewed in Fig. 2 and consequentlyreleases it from the pusher bar 50. Hence, while the pusher bar is heldby the lower feed clutch 62, the upper holding clutch 60 and the casingare moved upwardly relative to said pusher bar. A hook-shaped portion 88at the top of the pusher bar limits such relative movement between itand the upper holding clutch 60.

This process continues automatically and without the attention orconscious participation of the person using the pencil. As the lead isconsumed during the writing operation the casing and pusher bar descendwhile the guide and spacer bar assembly remain stationary. Once thepencil is lifted from the paper, the casing moves upwardly relative tosaid assembly while the pushser bar remains in its advanced position.When it is desired to replace the lead, the casing may be opened and thepusher bar pulled upwardly by means of its hook portion 88. To free itfor such movement, the right-hand end of the upper holding clutch 60 ispressed downwardly against the rod 66, causing said rod to pressdownwardly on the right-hand end of the lower feed clutch 62. Thiscauses the two clutches to swing in counter-clockwise direction and todisengage the pusher bar. A new stick of lead is inserted through thebottom end of channel 50 and the pusher bar is then moved downwardlyinto abutment with it. The clutch members are released and they onceagain engage the pusher bar preparatory to the operations abovedescribed. A stop member 90 secured to the casing 10 below theright-hand end of upper holding clutch 60 limits the downward movementof said clutch.

From the foregoing it will be understood that the lead cannot be seenwhen the pencil is held against the Writing surface. lt is enclosed onall sides by the tapered portions 28, 30, 36 and 38 of the guide andspacer bar assembly. The spacer bars and their tapered portions 36 and38 are made of the same thickness as the lead and said tapered portions36 and 38 are preferably colored black or any other color which wouldcontrast with the color of tapered portions 23 and 30, so as to mark theprecise location of the lead. 1t is by following tapered portions 36 and38 that the person using the pencil may properly and precisely positionand align the lead relative to the writing surface.

Turning now to the second form of this invention and to Figs. 8 to l2inclusive, it will be observed that the pencil 100 shown thereininvolves the same principle as the pencil iirst above described exceptthat it utilizes a cylindrical lead 102 instead of a rectangular lead42. Pencil 100 is provided with a casing 104 which may be hexagonal inshape as shown in Figs. 9 and l() but this is purely illustrative. lt issimply a tube which may be made in any desired cross-sectional shape.Screwed to the lower end of casing 104 is a tapered or conical nose 106through which a tubular sleeve 108 extends. The tapered nose 106 helpsposition the sleeve 108 and support it during the writing operation. Thelower end of sleeve 10S is rounded oft to provide a smooth bearingsurface relative to the writing surface but it is not as sharply roundedas the lower ends of tapered portions 26, 28, 36 and 38 above described.Sleeve 108 is adapted to receive the lead 102 and a pusher bar 110 whichprojects downwardly into the sleeve and into abutment with said lead.

Before feeding of the lead begins, the upper end of pusher bar 110 abutsa cup-shaped member 112 which occupies the upper end of casing 104.Cup-shaped member 112 is provided with a detent 114 which engages abayonet slot 116 in casing 104. It is by this means that the cup-shapedmember 112 may be held in place in the top of said casing to close ofithe top of the casing and for a further purpose. This purpose is tosupport a second cup-shaped member 118 in which is mounted an eraser120. Cup-shaped member 118 is provided with an embossment 122 whichengages a bayonet slot 124 in the cup member 112 so as to hold the cupmember 118 in place in the cup member 112. It will now be observed thata rod 126 is mounted within the casing 104, its upper end projectingthrough an opening 128 in cup member 112 and abutting the cup member118.

Rod 126 performs substantially the same function as rod 66 in the iirstform of this invention. There is a reduced portion 130 at the lower endof rod 126, providing a shoulder 132 between said reduced portion andthe main body of said rod. The reduced portion 130 projects through anopening in upper holding clutch 134 and the lower end of said reducedportion abuts a lower feed clutch 136. Shoulder 132 abuts the clutch134. A bearing 138 is connected to a cup-shaped member 140 and itsupports said lower reduced end 130 of rod 126 while permittinglongitudinal movement of said rod. A compression spring 142 is mountedbetween clutch 134 and bearing 138 and it tends to urge the clutch 134in clockwise direction as viewed in Fig. 8. The right-hand end of saidclutch 134 projects into an opening 144 in the casing 104 and edge 146defining the upper end of said opening serves as a fulcrum for saidclutch member 134. It is this action which causes clutch 134 to engagethe pusher rod 110, especially when the pencil is held to a writingsurface and the person using the pencil bears down upon the casing 104.This is precisely the same action as has above been described inconnection with the first form of this invention.

It will now be understood that sleeve 108 is fixed to the cup member 140which, as above indicated, is secured to the bearing 138. Consequently,an assembly consisting of sleeve 108, cup 140 and bearing 138 isprovided and this assembly will hereinafter be designated the sleeveassembly, corresponding to the guide and spacer bar assembly first abovedescribed. As the lead is consumed during a writing operation, thecasing 104, together with its tapered nose 106, its upper holding clutch134 and the pusher rod 110 will descend in direct proportion toconsumption of the lead.

When the pencil is lifted from the writing surface, spring 142' willpush said casing 104, the clutch 134 and the tapered nose 106 upwardlyrelative to the sleeve 108, the cup 140 and the bearing 138. It will nowbe noted that a second compression spring engages one end of clutch 136while the opposite end projects through an opening 152 in cup 140 andbears against the edge 154 which functions as a fulcrum. This clutch 136tends to lock the pusher rod 110 in place relative to the sleeve 108when the other spring 142 causes the casing 104, the clutch 134 andtapered nose 106 to move upwardly relative to said sleeve 108. This isprecisely the same action as has above been described in connection withthe iirst form of this invention.

When it is desired to release the two clutches from the push rod 110,cup-shaped member 118 with its eraser 120 are turned and by means ofbayonet slot 116, rod 126 is depressed.

Cylindrical lead 102 shown in Fig. 13 is conventional in shape. In Fig.13A is shown a similarly shaped lead 156 which is provided with aplurality of very fine longitudinally extending ribs 158. Three suchribs are shownl in the drawing but it will be understood that thisnumber is purely illustrative. These ribs 158 perform the same functionas ribs 48 above described. They are pressed between the main body ofthe lead and the cylindrical wall of sleeve 10S. A press-lit is therebyprovided between the lead and the sleeve which securely holds the leadin place except when it is advanced by the mechanism above described.The ribs (or fins) are shaved, compressed or crushed on the insertionwithin their tracks.

Although the pencil is shown in a vertical position `in Fig. 8, it isexpected that during use the pencil will be tilted to an angle inclinedfrom the vertical, such angle varying with the practices of theindividual users of the pencil. This is because the pencil shown in Fig.8 is intended to function as a writing pencil, as distinguished from adrawing or drafting pencil. The pencil shown in Figs. 1 and 2 isdesigned as a drafting pencil and is intended to be used in a generallyvertical position. The foregoing is not to be construed as limiting theuses of the two pencils but merely indicating the purposes for whichthey were primarily designed.

A sheet of paper 160 is shown disposed at an angle to the pencil in Fig.8. This sheet would normally occupy a horizontal plane and the pencil anangular position relative to said plane. But as above indicated, thepencil is shown in vertical position for illustrative purposes only. Itwill be observed that the lower end of sleeve 108 is cut oif at withonly a rounded peripheral edge, as distinguished from the fully roundedends of the tapered portions 28, 30, 36 and 38. Since the sleeve 108 isconsiderably larger in diameter than the lead which it holds, tilting ofthe pencil relative to the paper, as indicated in Fig. 8, will provide aspace below the sleeve into which the lead will project. If the lowerend of the sleeve were rounded off entirely as in the case of Figs. 1and 2, the lead would not project from the sleeve and it would notwrite.

Referring now to Figs. 14 and 15 and to the third form of thisinvention, a fully automatic pencil 200 is shown which includes amagazine 202 of leads 204 and means for replacing consumed leads withthe leads in the magazine. Speaking generally, pencil 200 corresponds topencil 100 and includes a casing 206 and a tapered or conical nose 208secured to the lower end of the casing. Within the casing is acup-shaped member 210 to which is secured a sleeve 212 which projectsthrough the conical nose 208. The upper end of sleeve 212 is providedwith a ared portion 214 to facilitate entry of the lead. A push rod 216is provided and this rod not only performs the functions of the pushrods 50 and 110 above mentioned but it also has the additional functionof pushing a new lead into the sleeve 212 in replacement of a consumedlead. Push rod 216 has a reduced lower end 218 and a reduced upper end220 with a shoulder 222 at the top of reduced end 218, and a secondshoulder 224 at the bottom of reduced end 220. A head 226 is provided atthe top of reduced end 226. There are two clutch members 230 and 232respectively which correspond to the clutch members of the first twoforms of the invention and perform the same functions.

More specifically, clutch member 230 projects through an opening 234 inthe casing 206 and it abuts edge 236 which serves as a fulcrum.Compression spring 238 rests upon the cup 210 and bears outwardlyagainst the clutch member 230. The lower clutch member 232 projectsthrough an opening 240 in cup 210 and it engages an edge 242 whichserves as a fulcrum. A spring 244 bears upwardly against clutch 232 anddownwardly against the magazine 202. Both springs tend to urge theclutches in clockwise direction about their respective fulcrums and boththereby cause the clutches to engage the push rod.

A leaf spring 250 is disposed within the magazine for engagement withthe leads therein and the leads are thereby urged radially inwardly, asviewed in Fig. 15, to the center of the casing. The innermost lead wouldthen be in alignment with sleeve 212 and the pusher rod. It is assumedthat it is now desired to write until the lowermost lead in sleeve 212is fully consumed. When this takes place, the reducer lower end 218projects through the magazine and occupies the position which is nowshown to be occupied by the stick of lead 204a. Lead 204b would be fullyconsumed and lead 204e would then occupy its position at the lower endof sleeve 212. By the same token, lead 204d would occupy the presentposition of 204C. It is now necessary to retract the push rod 216 fromthe position which is now shown to be occupied by lead 204a and toreturn it to the position which it is now shown to occupy in Fig. 14.

In order to do this, clutches 230 and 232 must be released from the pushrod 216. This is done by turning the top cap 260 until the cup-shapedcam member 260 which is secured to the lower end of said cap engagesrelease bar 264 and presses said bar downwardly. This release bar has ashoulder 266 which engages clutch 230 and a shoulder 268 which engagesclutch 232. When release bar 264 is depressed, these clutches are causedto swing in counterclockwise direction in order to release the push rod216. The push rod is now free to be retracted to the position which itis shown to occupy in Fig. 14.

Push rod 216 may be so retracted by simply pulling upwardly upon cap260. Secured to the inside of cap 260 by means of rivets 270 or anyother conventional means is a second cap 272. Secured to said second capis a rod 274 which projects downwardly through an opening in the cam cup262 and into casing 206. lt will new be observed that head 226 at thetop of push rod 216 is located immediately below rod 274. Said rod 274thereby serves as a stop member to prevent upward movement of the pushrod beyond its present position as shown in Fig. 14. Secured to rod 274by means of rivet 276 is a hook-shaped member 278 which is engageablewith head 226 when the push rod 216 is moved downwardly to the extent ofthe length of one of the leads. This hookshaped member 278 serves as astop to limit such downward movement of the push rod but it also servesas a hook for pulling the push rod upwardly to the position which it ispresently shown to occupy in Fig. 14. This is done by simply pullingupwardly upon cap 260 since the hook is secured to said cap by means ofrod 274 and inner cap 272. rThere is a cross plate 280 with a slot 282formed therein. This slot is large to accommodate the reduced upper end220 of the push rod but it is too small to pass either shoulder 224 orhead 226 and consequently the cross plate limits the upward movement ofthe push rod and prevents it from being pulled out of the casing. Oncethe push rod is retracted to its Fig. 14 position, lead 204g will bepushed into the position which it is now shown to occupy in Fig. 14 bymeans of spring 250.

In Figs. 16 and 17 is shown a modified version of the magazine shown inFigs. 14 and l5. In Figs. 14 and l5 the magazine holds the several leadsin a straight line and its capacity is limited to the radial distancebetween the center of the casing and spring 250; a pencil of relativelysmall diameter could accommodate a magazine 202 of only limitedcapacity. To overcome this limitation, the magazine 300 shown in Figs.16 and 17 occupies a spiral position, the inner end of the spiralcoinciding with the center of the casing and the outer end of the spiralbeing disposed adjacent the casing wall. This spiral magazine mayconsist of a single convolution or a part of a single convolution or aplurality of convolutions, and in the latter case its capacity would beextremely large. To urge the leads in spiral magazine 300 toward theinner end thereof, a torsion spring 362 is provided which winds aroundthe push rod 304. The upper end of said torsion spring is secured to abracket 306 which, in turn, is fastened to the casing 308. The lower endof the torsion spring is coiled as shown at 310 and it then is providedwith a lowermost portion 312 which projects downwardly into the magazineand abuts the last stick of lead therein.

Referring now to the nal form of this invention and to Figs. 18 and 19,a pencil 320 is shown to be provided which .is even more fully automaticthan that shown in Fig. 14. These two pencils are, essentially, alike,especially in their clutch, push rod and magazine elements.

'l'hey diler mainly in the means for retracting the push rod. This isdone manually in Fig. 14 and automatically in Fig. 18. Clutch members322 and 324 correspond to clutch members 230 and 232 shown in Fig. 14.But instead of coil spring 238 bearing up against clutch 230, a leafspring 326 bears up against clutch 322. Push rod 328 is like push rod216 eXcept that it is provided with a downwardly facing shoulder 330 inplace of upwardly facing shoulder 224 and in place of head 226 there isa hole 332 which is engaged by a tension spring 334. The upper end ofsaid spring is secured to cap 336. There is also a double shoulder 338between shoulder 330 and hole 332 on the push rod 328 which is not foundon push rod 216. The action of spring 334 is to draw push rod 328upwardly to its Fig. 18 position.

When push rod 328 descends in the normal course of use of the pencil andas the lead is consumed in such use, eventually shoulder 330 will engagethe top of release bar 340 and further downward movement of said pushrod will cause said release bar by means of its shoulders 342 and 344 torelease the two clutch members 322 and 324 from the push rod. Spring 334will thereupon pull the push rod upwardly. At the same time, a rocker3'46 pivoted on 348 and urged inwardly by leaf spring 350 will pivot inclockwise as soon as its lower end 352 clears the release lbar 340. Oncethis happens, the release bar will be held by said rocker against upwardmovement and the clutch members will be held in released position longenough to enable the push rod to rise under the inuence of spring 334 toits upper position.

As the push rod 328 thus moves upwardly, double shoulder 338 will engagepin 360 on plate 362. Plate 362 is pivotally mounted on pivot 364 andthis upward movement of the push rod will therefore cause the plate 362to pivot in counterclockwise direction about the pivot 364. It will nowbe observed that another pin 366 is secured to the free end of plate 362and said pin is engageable with a cam edge 368 on rocker 346. When thishappens, the rocker is caused to swing in counterclockwise directionagainst leaf spring 350. This returns the rocker to Fig. 18 position,releasing the release bar 340 for upward movement under the action ofsprings 326 and 370, thereby causing the clutch members to reengage thepush rod.

Plate 362 is normally held in horizontal position and the means whichaccomplishes this will now be described. It consists of a leaf spring380 which is secured at its outer end to the pencil casing 382, and apair of pins 384 and 386 which are secured to plate 362 and engageopposite sides of said leaf spring. Proper positioning of the plate 362is important since its position determines the moment of release of therelease bar 340.

The foregoing is illustrative of preferred forms of this invention andit will be understood that these forms may be modified and other formsmay 'be provided within the broad spirit of the invention and the broadscope of the claims.

I claim:

1. A mechanical pencil comprising a holder, a sleeve projectinglongitudinally from the lower end of said holder and being mounted forslidable movement relative to said holder longitudinally of itself andof the holder, said sleeve being adapted to receive a writing elementslidably mounted therein for longitudinal movement relative to saidsleeve, a pusher bar mounted in said holder and projecting downwardlyinto said sleeve for engagement with a writing element slidably mountedtherein, said pusher bar being disposed longitudinally of said holderand said sleeve and being mounted for longitudinal slidable movementrelative to said holder and said sleeve, and clutch means mounted in theholder and engaging said pusher bar to permit downward movement of saidpusher bar relative to said holder while preventing upward movement ofsaid pusher bar relative to said holder, the holder being provided withadditional clutch means mounted therein and engaging said pusher bar,said additional clutch means being connected to the sleeve and beingadapted to prevent upward movement of the pusher bar relative to saidsleeve while permitting downward movement of the pusher bar relative tothe sleeve, a connecting link being provided between the first c-lutchmeans and the additional clutch means, the rst clutch means beingmanually releasable from the pusher bar to permit upward movement of thepusher bar relative to the holder, the connecting link being adapted torelease the additional clutch means from the pusher bar when the firstclutch means is manually released therefrom, thereby permitting upwardmovement of said pusher bar relative to said sleeve, the lower end ofthe sleeve being provided with a bearing surface which is adapted tobear against a writing surface when the mechanical pencil is in use,whereby the sleeve is prevented from moving downwardly relative to saidwriting surface, the holder being adapted to move downwardly relative tosaid sleeve and said writing surface when the user of said mechanicalpencil bears down upon said holder with conventional writing pressure,whereby said writing pressure is transmitted through said holder, saidrst clutch means and said pusher bar to the writing element in thesleeve, spring means being provided between the holder and the sleeve tomove the holder upwardly relative to the sleeve and relative to theadditional clutch means and pusher bar when said holder is relieved ofsaid writing pressure, a magazine being provided in the holder for aplurality of writing elements, a portion of said magazine being disposedacross the path of the pusher bar and in alignment therewith and beingopen at its upper end to permit entry of said pusher bar and being openat its lower end to permit entry of a writing element into said sleeve,and spring means engageable with said writing elements to urge themseriatim into alignment with said pusher bar and said sleeve between thepusher bar and the sleeve.

2. A mechanical pencil in accordance with claim 1, wherein the magazinecomprises a narrow chamber extending radially outwardly in a straightline from the center of said holder, said pusher bar and said sleevebeing also disposed in the center of said holder.

3. A mechanical pencil in accordance with claim 1, wherein the magazinecomprises a narrow chamber extending spirally outwardly from the centerof said holder, said pusher bar and said sleeve being also disposed inthe center of said holder.

References Cited in the tile of this patent UNITED STATES PATENTS TM70,598 Automatic, Eagle Pencil Co Sept. 15, 1908 1,447,677 Lindberg Mar.6, 1923 1,633,529 Holman June 21, 1927 1,729,786 Lindberg Oct. 1, 19291,729,814 Becker Oct. 1, 1929 2,011,270 Chesler Aug. 13, 1935 2,107,816Chesler Feb. 8, 1938 2,469,411 Robbins May 10, 1949 2,492,839 BrubakerDec. 29, 1949 2,528,328 Baker et al. Oct. 31, 1950 2,646,775 VierlingJuly 28, 1953 FOREIGN PATENTS 12,383 Great Britain Dec. 21, 1848 358,292Germany Sept. 8, 1922

